October 09, 2018

On climate, our choice is now catastrophe or mere disaster

We are hurtling toward a multi-national pile-up, and we know it. Even if we slam on the brakes, the Special Report tells us, we’ll be seriously injured instead of maimed or killed. That is, no good consequences are foreseeable — only bad and less bad.

Not quite ghastly

So sea levels will still rise, and the oceans will still acidify, but less than if we crash through to 2 degrees Celsius. Fewer ecosystems will collapse and fewer species will go extinct. Extremely hot days will be 3 degrees warmer instead of 4 degrees. Droughts and storms won’t be quite as bad at 1.5 degrees as at 2 degrees. The Antarctic and Greenland ice sheets will be somewhat more stable and less likely to collapse. About 10 to 30 per cent of coral reefs will survive at 1.5 degrees; at 2 degrees, they’ll all die. Instead of losing a global fishery catch of 3 million tonnes at 2 degrees, we’ll lose only 1.5 million tonnes at 1.5 degrees.

Of interest to Canadians, “Limiting global warming to 1.5 degrees rather than 2 degrees is projected to prevent the thawing over centuries of a permafrost area in the range of 1.5 to 2.5 million km2.”

The Special Report says surprisingly little about the health and social consequences of further warming. At 1.5 degrees we’ll see fewer heat waves and disease outbreaks than at 2 degrees, and crop losses won’t be quite as bad, and water won’t be quite as scarce. The consequences will be worst for the poor tropical nations that have contributed least to the warming problem, but not quite as bad at 1.5 degrees as at 2. The social and political consequences go unmentioned except as abstractions: “Hazards, exposures, and vulnerabilities that could affect increasing numbers of people and regions.”

More concretely, the world (including us) will be involved in wars, revolutions, mass displacement of millions of people, famines, and epidemics. And that’s the better of the two scenarios.

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We are hurtling toward a multi-national pile-up, and we know it. Even if we slam on the brakes, the Special Report tells us, we’ll be seriously injured instead of maimed or killed. That is, no good consequences are foreseeable — only bad and less bad.

Not quite ghastly

So sea levels will still rise, and the oceans will still acidify, but less than if we crash through to 2 degrees Celsius. Fewer ecosystems will collapse and fewer species will go extinct. Extremely hot days will be 3 degrees warmer instead of 4 degrees. Droughts and storms won’t be quite as bad at 1.5 degrees as at 2 degrees. The Antarctic and Greenland ice sheets will be somewhat more stable and less likely to collapse. About 10 to 30 per cent of coral reefs will survive at 1.5 degrees; at 2 degrees, they’ll all die. Instead of losing a global fishery catch of 3 million tonnes at 2 degrees, we’ll lose only 1.5 million tonnes at 1.5 degrees.

Of interest to Canadians, “Limiting global warming to 1.5 degrees rather than 2 degrees is projected to prevent the thawing over centuries of a permafrost area in the range of 1.5 to 2.5 million km2.”

The Special Report says surprisingly little about the health and social consequences of further warming. At 1.5 degrees we’ll see fewer heat waves and disease outbreaks than at 2 degrees, and crop losses won’t be quite as bad, and water won’t be quite as scarce. The consequences will be worst for the poor tropical nations that have contributed least to the warming problem, but not quite as bad at 1.5 degrees as at 2. The social and political consequences go unmentioned except as abstractions: “Hazards, exposures, and vulnerabilities that could affect increasing numbers of people and regions.”

More concretely, the world (including us) will be involved in wars, revolutions, mass displacement of millions of people, famines, and epidemics. And that’s the better of the two scenarios.